JP2018066772A - Optical laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical laminate 1 that can solve, in particular, a problem of fusing between ends after a thermal bending process and a problem of lifting at an end or generation of a filament-like substance in a die-cutting process.SOLUTION: The optical laminate 1 has a basic structure comprising an optical functional layer 5 sandwiched between a pair of transparent sheets 3 and has a protective film 9 directly laminated on the surface of at least one transparent sheet 3. The protective film 9 comprises at least a base layer 9a containing a first polyolefin resin and inorganic particles and having a melting point ranging from 150°C to 175°C, and an inner layer 9b containing a second polyolefin resin and having a melting point ranging from 100°C to 125°C, in which the inner layer 9b adheres to the surface of the transparent sheet 3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical laminate including an optical functional layer exhibiting optical functions such as photochromic properties and polarization properties. More specifically, the present invention relates to an optical laminate in which an optical functional layer is sandwiched between a pair of transparent sheets, and a protective film is directly laminated on the surface of at least one transparent sheet.

  In recent years, there has been a rapid increase in demand for plastic substrates using transparent and excellent impact-resistant polycarbonate for anti-glare sunglasses and the like. And in such plastic sunglasses, plastic photochromic sunglasses that can adjust the antiglare property by changing the transmittance according to the surrounding brightness by combining with the photochromic compound are rapidly gaining popularity. .

  For example, Patent Document 1 discloses an optical laminate in which a photochromic layer is laminated between two polycarbonate sheets. Patent Document 2 discloses an optical laminate in which a polarizing layer is laminated between two polycarbonates.

  An optical laminate including an optical functional layer such as a photochromic layer or a polarizing layer as described above is generally processed into a desired shape by hot bending. In this thermal bending process, an optical laminate is placed on a mold (mold) that has been digged into a desired shape, and is heated (under a temperature near the glass transition temperature of the laminate). And by shaping under pressure or reduced pressure (vacuum). Moreover, the optical layered body is generally die-cut into a desired shape before or after the heat bending process.

  By the way, a plastic sheet such as polycarbonate is likely to be scratched, dirty, or foreign. For this reason, a protective film is usually provided on the surface of the plastic sheet for the purpose of protecting the surface at the time of the hot bending process, die cutting process, storage, and transportation. As such a protective film, for example, a polyolefin film such as polyethylene or polypropylene is used. Such a protective film is peeled off when the optical laminate is used as a final product such as a spectacle lens.

  For example, Patent Document 3 discloses a protective film having a first film layer disposed on the side in contact with the mold and a second film layer disposed on the polycarbonate sheet side. In the protective film, the first film layer is a polyolefin film layer having a melting point of 150 ° C. or higher, the second film layer is a polyolefin film layer having a melting point of 125 to 145 ° C., and the second film layer and the polycarbonate sheet Between the two, a polyethylene-based adhesive layer is provided. The protective film having such a structure is excellent in heat resistance and can effectively prevent adhesion of the protective film to the mold surface during hot bending.

  Furthermore, Patent Document 4 proposes a protective film composed of a base material layer and an adhesive layer. This protective film has a melting peak (A) of 105 to 130 ° C. and a melting peak (B) of 160 to 175 ° C., and the area ratio [(A) / (B)] of the melting peak is 35. / 65 to 80/20. By using this protective film, it is possible to suppress the occurrence of filaments (such as burrs) from the end of the protective film during the die cutting process, and it is possible to fuse the protective film to the mold by hot bending. Wear can be suppressed.

  However, the conventionally known optical laminate having the above-described structure has a poor appearance due to a so-called adhesive residue (adhesive adhesion) when the protective film is peeled off after the heat bending process. Or there existed a problem of a fall of an optical characteristic, and also there existed a problem which the fusion | melting to the metal mold | die of the protective film at the time of a heat bending process produced. Further, at the time of die cutting of the optical laminate, floating of the end portion of the protective film and a thread-like material are generated, and these cause defective molding when the optical laminate is subjected to hot bending after die cutting.

Japanese Patent No. 4661017 Japanese Patent No. 2130732 Japanese Patent No. 3856107 Japanese Patent No. 5724174

  Further, it has been found that when the present inventors use a conventionally known optical laminate to manufacture a hot-bending product, the following problems further occur. That is, in the heat-bending product obtained by forming the concavo-convex structure by placing the optical laminate on a concave mold and sucking under reduced pressure from the hole in the center of the mold, the surface with the convex mold is attached. In some cases, an end portion of a certain protective film is covered so as to overlap an end portion of the protective film on the surface with the concave mold, and the covered portion is fused. When such a phenomenon occurs, it takes time to peel off the protective film, which may reduce the product yield. In addition, since a part of the protective film is likely to be fused and remain at the end, the yield of the product may be reduced. Especially when the temperature at the time of hot bending is set to a relatively high temperature or when the heat bending process is carried out for a relatively long time, the edge of the convex protective film and the edge of the concave protective film are bonded. In some cases, the yield was further reduced.

  Accordingly, the object of the present invention is to solve the problem of adhesive residue when the protective film is peeled off, as well as the fusion of the protective film to the mold during hot bending and the floating of the end of the protective film during die cutting. Another object of the present invention is to provide an optical laminate with a protective film that solves the problem of generation of yarns and filaments. Furthermore, the objective of this invention is providing the said optical laminated body which can suppress the overlap of the edge parts of a protective film, melt | fusion, etc. which generate | occur | produce at the time of a heat bending process, and can improve the yield of a heat bending process goods. .

  In order to solve the above problems, the present inventor has intensively studied. And in the temperature range at the time of a heat bending process, examination of the protective film which improved heat resistance and with few deformation | transformation was advanced. As a result, the base material layer having the largest thickness is composed of a specific resin and a composition containing inorganic particles, and it is found that the above-mentioned problem can be solved by configuring the surface in contact with the transparent sheet with the specific resin. The present invention has been completed.

That is,
In the optical laminate in which the optical functional layer has a basic structure sandwiched between a pair of transparent sheets, and a protective film is directly laminated on the surface of at least one transparent sheet.
The protective film is
A base material layer containing 5 to 50 parts by mass of inorganic particles with respect to 100 parts by mass of the first polyolefin-based resin and having a melting point in the range of 150 ° C. or higher and 175 ° C. or lower;
Including a second polyolefin-based resin, and having at least two layers with an inner layer having a melting point in the range of 100 ° C. or more and 125 ° C. or less,
The optical layered body is characterized in that the inner layer is in close contact with the surface of the transparent sheet.

In the first aspect of the present invention, the heat resistance of the protective film itself is further improved, and further, when the protective film is formed or stored, the inorganic particles of the base material layer are prevented from being transferred to the inner layer, and the transparent sheet In order to improve the adhesion to
The protective film is
It is preferable that the base layer on the side opposite to the inner layer further includes three outer layers including a third polyolefin resin and having a melting point of 150 ° C. or higher and 175 ° C. or lower.

  Moreover, in order to further suppress the appearance defect of the heat-bending product and further improve the yield, the thickness of the protective film is 30 μm or more and 200 μm or less, and when the thickness of the inner layer is 1, It is preferable that the thickness ratio of the base material layer is 2 to 10, and the thickness ratio of the outer layer is 0.5 to 2.

  In the first aspect of the present invention, the effect is particularly exerted in the case of an optical laminate in which the protective film is directly laminated on the surfaces of both transparent sheets.

  In the protective film, in order to further improve the film forming property and heat resistance of the protective film, the inorganic particles are preferably calcium carbonate.

  In the first aspect of the present invention, when the transparent sheet is a polycarbonate sheet and the optical functional layer contains a photochromic compound and a urethane resin, an excellent effect is exhibited.

The second aspect of the present invention is a die-cut product comprising the optical laminate,
The third aspect of the present invention is a hot-bending product made of the optical laminate.

  According to the present invention, in a heat-bending product, an appearance defect due to a so-called adhesive residue (adhesive adhesion) when the protective film is peeled off is suppressed, and a molded product with good optical properties (hereinafter, the protective film is peeled off). For example, a product such as a lens may be simply referred to as a “molded product”. Therefore, when the molded product has photochromic characteristics, it can have excellent characteristics. Furthermore, according to this invention, the fusion | fusion to the metal mold | die of the protective film at the time of a heat bending process can be suppressed. Moreover, at the time of die-cutting, it is possible to suppress the floating of the end portion of the protective film and the occurrence of thread-like material, and as a result, it is possible to suppress molding defects of a molded product obtained by performing hot bending after die-cutting. In addition, it is possible to suppress the adhesion (fusion) between the protective films during the hot bending process, and to improve the yield of the molded product.

It is a figure which shows an example of the schematic of the cross-section of the optical laminated body of this invention. It is a figure which shows an example of the schematic of the cross-section of the protective film 9 used by this invention.

  The optical laminated body 1 of this invention is demonstrated using FIG. FIG. 1 is a schematic view showing a cross-sectional structure of the optical laminate 1. The optical laminate 1 has a basic layer structure in which an optical functional layer 5 is sandwiched between a pair of transparent sheets 3 and 3. In the above basic structure, the optical functional layer 5 is appropriately bonded to the transparent sheet 3 by the adhesive layer 7. Further, as shown in FIG. 1, a protective film 9 is provided on the surface of the transparent sheet 3.

  This protective film 9 should just exist at least on the surface which touches a metal mold | die when carrying out a heat bending process. For example, when both surfaces of the optical laminate 1 are in contact with a mold, it is preferable to directly laminate both surfaces of the transparent sheets 3 and 3. Further, if only one surface is in contact with the mold, it is sufficient that at least the protective film 9 exists on the surface. However, in order to protect the surface of the die-cut product and the heat-bending product and prevent scratches on the finally obtained molded product, the protective film 9 is provided on both surfaces of the transparent sheets 3 and 3. Direct lamination is preferred.

(Transparent sheet 3)
In the optical laminate 1 of the present invention, the transparent sheet 3 may be colored in a desired color, but has transparency so as not to hinder the optical function of the optical function layer 5 described later. For example, a light transmittance of 50% or more for light having a wavelength of 500 nm is preferably used.

  Examples of such a transparent sheet include polycarbonate resin, polyethylene terephthalate resin, nylon resin, triacetyl cellulose resin, acrylic resin, urethane resin, allyl resin, epoxy resin, and polyvinyl alcohol resin. Among them, a polycarbonate sheet is preferable in that it has excellent adhesion to an optical functional layer and the like and is excellent in injection moldability. In particular, since the polycarbonate resin is hard and the surface is easily damaged, the effect of providing the protective film 9 is more exhibited.

  Furthermore, the transparent sheet 3 may have a hard coat layer or the like laminated on the surface thereof before the optical laminate 1 is manufactured.

  The thickness of the transparent sheet 3 is not particularly limited as long as it has an appropriate thickness depending on the use of the optical laminate 1, but is generally 100 to 1500 μm, particularly preferably 200 to 1000 μm. . Of course, the thickness of the two transparent sheets 3 and 3 may be different.

(Optical function layer 5)
The optical functional layer 5 is a layer showing an optical function represented by photochromic properties and polarization properties, and is a layer in which an optical functional material showing such an optical function is dispersed in a binder resin. Examples of the optical functional material include a photochromic material and a polarizing material. This optical functional layer 5 may be a layer formed of two layers of a photochromic layer and a polarizing layer.

  As the photochromic material, a photochromic compound known per se, for example, a chromene compound, a fulgimide compound, a spirooxazine compound, a spiropyran compound or the like is used alone or in combination of two or more.

  Examples of the fulgimide compound, spirooxazine compound, spiropyran compound, and chromene compound described in JP-A-2-28154, JP-A-62-2288830, WO94 / 22850, WO96 / 14596, etc. Can be mentioned.

  Among these photochromic compounds, 1 is a chromene compound having an indeno (2,1-f) naphtho (2,1-b) pyran skeleton from the viewpoint of photochromic properties such as color density, initial coloring, durability, and fading speed. It is more preferable to use more than one type. Further, among these chromene compounds, compounds having a molecular weight of 540 or more are preferable because they are particularly excellent in color density and fading speed.

  Such a photochromic compound exhibits sufficient photochromic properties (color density, fading speed, photochromic durability), is uniformly dispersed in the binder resin, and further from the viewpoint of adhesiveness to the transparent sheet 3, etc. Generally, the amount is 0.1 to 20 parts by mass, particularly 0.5 to 10 parts by mass, and most preferably 1 to 7 parts by mass, per 100 parts by mass of the binder resin.

  As the polarizing material, iodine, iodine compound, or dichroic dye can be used. Such a polarizing material is generally used in an amount of about 0.1 to 5 parts by mass per 100 parts by mass of the binder resin.

  As the binder resin, an appropriate one is used according to the kind of the optical functional material described above. For example, when a polarizing material is used as an optical functional material, a water-soluble resin such as polyvinyl alcohol is preferably used, and the polarizing property can be increased by uniaxially stretching such a binder resin impregnated with a polarizing material. The optical functional layer 5 shown can be formed.

  Moreover, when using a photochromic compound as an optical functional material, a urethane resin or a (meth) acrylic resin is preferably used, and from the viewpoint of adhesion to the transparent sheet 3, a urethane resin is most preferable. The above urethane resin is a resin having a urethane bond in the molecule, and specifically, a known resin obtained by reacting a diisocyanate compound such as isophorone diisocyanate with a polyol compound such as polycarbonate polyol or polyester polyol. used. Of these, urethane-urea resins obtained by reacting chain extenders such as diamine and triamine are preferred. Further, by using it as a diamine or triamine chain extender, a urea bond (—R—NH—CO—NH—) is introduced into the urethane resin to form a urethane-urea resin.

  As said urethane resin, the urethane resin described in Japan patent 5863317, Unexamined-Japanese-Patent No. 2012-207198 etc. can be used, for example. Moreover, the adhesive force of the optical laminated body obtained using the said urethane resin can be improved by post-adding the polyisocyanate compound which has two or more isocyanate bonds in a molecule | numerator further with respect to said urethane resin. . This is because the urethane resin and the isocyanate compound added later separately react to form a polyurethane resin having a bridge structure, and heat resistance is improved and cohesive failure is less likely to occur. Conceivable.

  The urethane resin particularly preferably used in the present invention preferably has a softening point of 80 to 150 ° C. in that it has good heat resistance and does not inhibit the photochromic properties of the photochromic compound.

  Although the thickness of the optical function layer 5 described above is set to an appropriate thickness according to the optical function, it is usually desirable to be in the range of 10 to 500 μm.

  Further, in such an optical function layer 5, an amount as long as an additive known per se does not impair the optical function, for example, an amount of 20 parts by mass or less, more preferably 3 parts by mass or less per 100 parts by mass of the binder resin. It may be blended with. Such additives include surfactants, antioxidants, radical scavengers, UV stabilizers, UV absorbers, mold release agents, anti-coloring agents, antistatic agents, fluorescent dyes, dyes, pigments, perfumes, plastics. Agents and the like.

(Adhesive layer 7)
The optical functional layer 5 described above is appropriately bonded to the transparent sheet 3 via the adhesive layer 7. Although it does not restrict | limit especially as an adhesive agent used for formation of the contact bonding layer 7, The urethane resin mentioned above is used suitably also as an adhesive agent. The thickness of the adhesive layer 7 is usually about 2 to 40 μm.

(Protective film 9)
The protective film 9 is used to protect the surface of the transparent sheet 3 and prevent the surface from being scratched or soiled, and is a molded product finally obtained from the optical laminate 1, for example, When used as an optical article, it is peeled off from the surface of the transparent sheet 3.

An example of the protective film 9 used in the present invention will be described with reference to FIG. The protective film 9 is
Substrate layer 9a containing the first polyolefin resin and inorganic particles and having a melting point in the range of 150 ° C. or more and 175 ° C. or less (however, the inorganic particles are contained in an amount of 5 to 50 masses per 100 mass parts of the first polyolefin resin. Part)
It includes at least two layers including the second polyolefin resin and the inner layer 9b having a melting point in the range of 100 ° C. or more and 125 ° C. or less.

  The inner layer 9b is in close contact with the surface of the transparent sheet 3. The protective film 9 used in the present invention has at least two layers of the base layer 9a and the inner layer 9b (in the case of two layers, the inner layer 9b and the base layer 9a are laminated). If it is a structure, it may have other layers. For example, as long as the effect of the present invention is not impaired, another layer may be provided between the base material layer 9a and the inner layer 9b, or outside the base material layer 9a (the side opposite to the inner layer 9b). ) May be provided with other layers. The number of other layers is not particularly limited, but is 1 to 5 in consideration of the productivity of the protective film 9 itself.

Especially, as shown in FIG. 2, it is preferable to provide the outer layer 9c (outermost layer 9c) outside the base material layer 9a (on the base material layer 9a opposite to the inner layer 9b). Although detailed below, one of the reasons is as follows. Usually, the protective film 9 is manufactured as a roll-shaped roll. Therefore, in the case of two layers of the base material layer 9a and the inner layer 9b, the base material layer 9a and the inner layer 9b are in contact with each other when manufactured and stored as the scroll. Therefore, there is a possibility that inorganic particles contained in the base material layer 9a may be transferred / transferred to the inner layer 9b, and it is preferable to provide the outer layer 9c in order to prevent this. Further, the outer layer 9c is not particularly limited, but the protective film 9 includes a third polyolefin resin and has a melting point in the range of 150 ° C. or higher and 175 ° C. or lower in order to exert an excellent effect. The outer layer 9c is preferable.
Next, each layer which comprises these protective films 9 is demonstrated.

(Protective film 9; base material layer 9a)
The base material layer 9a is a layer containing a first polyolefin resin and inorganic particles and having a melting point of 150 ° C. or higher and 175 ° C. or lower. The melting point of the base material layer 9a is determined by the resin constituting it. This melting point can be determined by directly measuring the protective film 9 using a DSC (differential scanning calorimeter) described in Examples. The measurement of the melting point is a peak top value that can be measured according to JIS-K7121, and is the melting point of the resin whose main component is the heat of fusion.

  When the melting point of the base material layer 9a is less than 150 ° C., the protective film 9 may be fused to the mold during hot bending, which is not preferable. Moreover, when it exceeds 175 degreeC, there exists a possibility that it cannot be bent in a desired shape at the time of a heat bending process. Furthermore, for example, when polycarbonate or the like is used as the transparent sheet 3, it is not preferable because the protective film 9 is likely to be wrinkled during the heat bending process and the appearance of the heat bent product may be deteriorated. . Therefore, it is preferable that melting | fusing point of the base material layer 9a is 155 degreeC or more and 165 degrees C or less.

  Depending on the film forming conditions of the protective film 9, the melting point of the first polyolefin resin and the melting point of the base material layer 9a are slightly different values. However, in order to facilitate the film forming property of the protective film 9 itself, the melting point of the first polyolefin resin itself is preferably in the range of 150 ° C. or higher and 175 ° C. or lower, and in the range of 155 ° C. or higher and 165 ° C. or lower. It is more preferable that Therefore, as the first polyolefin resin, a propylene resin selected from homopolypropylene, propylene-α-olefin copolymer, for example, propylene-ethylene random copolymer, propylene-ethylene block copolymer, etc. should be used. Is preferred. The propylene-based resin may be obtained by polymerization using a known catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst.

  Moreover, the base material layer 9a contains inorganic particles. By including the inorganic particles, the heat resistance of the protective film 9 can be improved. As a result, fusion between the protective films 9 can be suppressed. Moreover, the action mechanism of including the inorganic particles can be considered as follows. That is, since the heat resistance can be improved and the crystalline resin component can be reduced, the yield point of the protective film 9 does not appear clearly near the heat bending temperature (for example, 130 ° C.). This means that even when the protective film 9 is stretched in the vicinity of the processing temperature, necking is unlikely to occur, and the ends of the protective film 9 on the surfaces of both transparent sheets 3 and 3 are prevented from being fused together. It is estimated that the effect can be demonstrated.

  In the base material layer 9a, the blending ratio of the first polyolefin resin and the inorganic particles must be 5 parts by mass or more and 50 parts by mass or less of the inorganic particles with respect to 100 parts by mass of the first polyolefin resin. By including inorganic particles in this range, even when placed at a high temperature (specifically, a temperature range of 130 to 150 ° C.) for a relatively long time (5 to 30 minutes) during hot bending, The protective film 9 can be peeled off from the hot-bending product while suppressing the tearing (breaking) of the protective film 9. As a result, the productivity of the molded product can be further increased. Furthermore, in addition to this effect, in order to further improve the operability during die cutting (ease of punching), heat resistance during hot bending, and anti-fusing properties, 100 mass of the first polyolefin resin More preferably, the inorganic particles are contained in an amount of 5 to 30 parts by mass, and more preferably 7 to 20 parts by mass.

  The inorganic particles are not particularly limited, and known materials can be used. Specifically, inorganic salts such as calcium carbonate, barium sulfate, calcium sulfate, barium carbonate, magnesium hydroxide, aluminum hydroxide, inorganic oxides such as zinc oxide, magnesium oxide, titanium oxide, silica, mica, vermiculite, talc Silicates such as can be used. Moreover, these can also be used individually or in mixture of multiple types. Commercially available inorganic particles can be used. In addition, in order to improve the dispersibility in the first olefin resin, a surface treated with a fatty acid (for example, stearic acid), a fatty acid salt (for example, calcium stearate), a wax, a coupling agent, or the like is used. be able to.

  Among these, it is preferable to use calcium carbonate in consideration of cost and film forming property. Calcium carbonate is produced by chemical reaction such as heavy calcium carbonate produced by mechanically pulverizing and classifying calcite-type crystalline limestone with good purity, carbon dioxide compounding method, calcium chloride soda method, lime soda, etc. Any particle such as light calcium carbonate produced in a wet manner can be used without limitation.

As the inorganic particles, those having a known shape blended in a normal film can be used as long as they do not cause pinholes. Although not particularly limited, it is preferable that the average particle size is 0.1 to 10 μm in consideration of mechanical properties, film forming properties, and the like. The specific surface area is not particularly limited, but is preferably 2000 to 35000 cm ² / g.

  The base material layer 9a may contain known additives in addition to the first polyolefin resin and the inorganic particles. Specific examples include additives such as antioxidants, lubricants, light stabilizers, surfactants (antistatic agents), conductive materials, and antiblocking agents. Moreover, in the range which does not impair the effect of this invention, other polyolefin resin, for example, the 2nd polyolefin resin explained in full detail below, can be included. Specifically, 1-100 mass parts of other polyolefin resin, for example, 2nd polyolefin resin, can also be included with respect to 100 mass parts of 1st polyolefin resin.

(Protective film 9; inner layer 9b)
In the present invention, the inner layer 9 b in the protective film 9 contains the second polyolefin resin, has a melting point in the range of 100 ° C. or more and 125 ° C. or less, and is laminated directly on the transparent sheet 3.

  When the melting point of the inner layer 9b is 100 ° C. or more and 125 ° C. or less, the adhesion with the transparent sheet 3 is improved, and peeling of the protective film 9 during processing can be suppressed. When the melting point of the inner layer 9b is less than 100 ° C., the protective film 9 may be fused to the mold during hot bending, which is not preferable. When exceeding 125 degreeC, since adhesiveness with the transparent sheet 3 falls, it is unpreferable. From the viewpoint of preventing fusion and improving adhesion, the melting point of the inner layer 9b is preferably 100 ° C. or higher and 123 ° C. or lower.

  Depending on the film forming conditions of the protective film 9, the melting point of the second polyolefin resin and the melting point of the inner layer 9b are slightly different values. However, in order to facilitate the film forming property of the protective film 9 itself, the melting point of the second polyolefin resin itself is preferably in the range of 100 ° C. or more and 125 ° C. or less. Therefore, as the second polyolefin resin, it is preferable to use an ethylene resin selected from polyethylene and an ethylene-α-olefin copolymer. As the ethylene-based resin, those obtained by polymerization using a known catalyst can be used. For example, those obtained by polymerization using a known catalyst such as a radical polymerization initiator, a Ziegler-Natta catalyst, or a metallocene catalyst can be used. The ethylene-based resin may be a resin selected from high-density polyethylene, low-density polyethylene, and linear low-density polyethylene. Among them, linear low-density polyethylene is used in consideration of adhesion. It is preferable. By using linear low-density polyethylene, it is not necessary to mix tackifiers such as terpene resin, hydrogenated terpene resin, rosin resin, and phenol resin in the inner layer 9b. As a result, it is possible to suppress the appearance defects of the hot-bending product and the molded product. Among linear low-density polyethylenes, in order to obtain a protective film that exhibits particularly excellent effects, a combination of ethylene and an α-olefin having 6 or more carbon atoms (for example, 1-hexene, 1-octene) is used. It is preferable to use linear low density polyethylene made of a polymer.

  The inner layer 9b may contain a known additive in addition to the second polyolefin resin. Specific examples include additives such as antioxidants, lubricants, light stabilizers, surfactants (antistatic agents), conductive materials, and antiblocking agents. Moreover, other polyolefin-type resin can be included in the range which does not impair the effect of this invention. However, when other olefin resin is included, it is 5 mass parts or less with respect to 100 mass parts of 2nd polyolefin resin. In consideration of adhesion and the like, the other polyolefin resin is preferably 0 part by mass.

  The protective film 9 used in the present invention must have a structure having at least two layers of the base material layer 9a and the inner layer 9b. And as above-mentioned, in order to maintain the performance with which the protective film 9 was excellent, it is preferable to provide the outer layer 9c as an outermost layer on the said base material layer 9a on the opposite side to the said inner layer 9b (FIG. 2). reference).

(Protective film 9; outer layer 9c)
In this invention, it is preferable that the outer layer 9c in the protective film 9 contains 3rd polyolefin resin, and has melting | fusing point in the range of 150 to 175 degreeC.

  When the melting point of the outer layer 9c is 150 ° C. or higher and 175 ° C. or lower, the heat resistance of the protective film 9 is improved, and further, the effect of preventing fusion is improved. When the melting point of the outer layer 9c is less than 150 ° C., the number of cases where the protective film 9 is fused to the mold during hot bending tends to increase, and the protective films 9 tend to be easily fused together. is there. Moreover, when it exceeds 175 degreeC, there exists a possibility that productivity of protective film 9 itself may fall. Furthermore, for example, when polycarbonate or the like is used as the transparent sheet 3, wrinkles or the like are likely to enter the protective film 9 during the hot bending process, and there is a possibility that the appearance defect of the hot bent product will be caused. Therefore, the melting point of the outer layer 9c is preferably 155 ° C. or higher and 165 ° C. or lower.

  Depending on the film forming conditions of the protective film 9, the melting point of the third polyolefin resin and the melting point of the outer layer 9c are slightly different values. However, in order to facilitate the film forming property of the protective film 9 itself, the melting point of the third polyolefin resin itself is preferably in the range of 150 ° C. or higher and 175 ° C. or lower, and the range of 155 ° C. or higher and 165 ° C. or lower. It is more preferable that Therefore, as the first polyolefin resin, a propylene resin selected from homopolypropylene, propylene-α-olefin copolymer, for example, propylene-ethylene random copolymer, propylene-ethylene block copolymer, etc. should be used. Is preferred. The propylene-based resin may be obtained by polymerization using a known catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst. Among these, considering the productivity of the protective film 9, for example, the reuse of the film edge (ear part) during film formation, the third polyolefin resin may be the same as the first polyolefin resin. preferable.

  Further, the outer layer 9c may be laminated with other layers, but is preferably the outermost layer of the protective film 9. In the roll product in the case where the protective film 9 is formed, the outer layer 9c becomes the outermost layer, so that the inner layer 9b comes into contact immediately above the outermost layer. At this time, since the outermost layer (outer layer 9c) is formed from a highly crystalline third polyolefin resin having a melting point of 150 ° C. or higher and 175 ° C. or lower, the inner layer 9b and the outermost layer (outer layer 9c) Adhesiveness falls and the protective film 9 can be easily taken out from a roll-like thing. Furthermore, since the base material layer 9a is not in direct contact with the surface of the inner layer 9a that contacts the transparent sheet 3, the inorganic particles, additives, and the like in the base material layer 9a are transferred to the above surface of the inner layer 9a. It will not be transferred. As a result, the adhesion of the protective film 9 can be improved.

  The outer layer 9c can contain known additives in addition to the third polyolefin resin. Specific examples include additives such as antioxidants, lubricants, light stabilizers, surfactants (antistatic agents), conductive materials, and antiblocking agents. Moreover, other polyolefin-type resin can be included in the range which does not impair the effect of this invention. However, when it contains other olefin resin, it is 5 mass parts or less with respect to 100 mass parts of 3rd polyolefin resin. In consideration of adhesion and the like, the other polyolefin resin is preferably 0 part by mass.

(Other properties of protective film 9, analysis method, production method, etc.)
As for the said protective film 9 used by this invention, it is preferable that the thickness (Hereinafter, it may be set as full thickness) which added each layer is 30-200 micrometers. Among them, when the thickness of the inner layer 9b is 1, the thickness ratio of the base material layer 9a is 2 to 10, and the thickness ratio of the outer layer 9c provided as necessary is 0.5 to 2 is preferable.

  In addition, when the said protective film 9 consists of two layers, the said base material layer 9a and the said inner layer 9b, the said total thickness is a total thickness of these two layers. When the protective film 9 is composed of three layers, the inner layer 9b, the base material layer 9a, and the outer layer 9c, the total thickness is the sum of the inner layer 9b, the base material layer 9a, and the outer layer 9c. It is thickness.

  When the total thickness satisfies the above range, and the ratio of the thickness of the inner layer 9b, the base material layer 9a, and the outer layer 9c provided as necessary satisfies the above range, the performance and operability as a protective material. , And heat resistance can be improved. In order to further improve the effect, the total thickness is preferably 50 to 150 μm, and the ratio of the thicknesses of the respective layers is such that when the thickness of the inner layer 9b is 1, the ratio of the thickness of the base material layer 9a is It is 3-10, and it is preferable that the ratio of the thickness of the outer layer 9c provided as necessary is 0.5-2. Furthermore, the total thickness is preferably 50 to 120 μm, and the ratio of the thicknesses of the respective layers is 5-10 when the thickness of the inner layer 9b is 1, and the ratio of the thickness of the base material layer 9a is necessary. It is preferable that the thickness ratio of the outer layer 9c provided in accordance with is set to 0.5 to 2.

  Moreover, when the protective film 9 used by this invention consists of three layers, the said base material layer 9a, the said inner layer 9b, and the said outer layer 9c, it is preferable to satisfy the following requirements. In the inner layer 9b, the base material layer 9a, and the outer layer 9c (the base material layer 9a and the outer layer 9c may be collectively referred to simply as “high melting point layer 9d”), 80 mainly derived from the inner layer 9b. The area ratio ((I) / (II)) of the heat of fusion (I) of ~ 135 ° C and the heat of fusion (II) of 145 to 175 ° C mainly derived from the high melting point layer 9d is 60/40 to 99 / A range of 1 is preferable. The heat of fusion can be measured by the same method as measuring the melting point of each layer. By satisfying this range, it is possible to improve the adhesion of the protective film 9 and suppress appearance defects during hot bending. Moreover, generation | occurrence | production of the film waste etc. at the time of a die cutting process can be suppressed. The amount of heat of fusion can be adjusted by the type of polyolefin resin used, crystallinity, thickness of each layer, film forming conditions, and the like.

  In the present invention, in order to confirm the melting point, heat of fusion, thickness, etc. of the protective film 9 to be used, the following methods can be employed. When the protective film 9 is formed, the first polyolefin resin, the second polyolefin resin, the third polyolefin resin, and inorganic particles may be used so as to satisfy desired physical properties. As a method for analyzing the protective film 9 after film formation, for example, the following method can be adopted. The case where the said protective film 9 consists of three layers of the said inner layer 9b, the base material layer 9a, and the outer layer 9c is demonstrated. First, analysis of the front surface and back surface of the protective film 9 (for example, analysis by a reflection method using a Fourier transform infrared spectrophotometer (FT-IR) or the like) is performed to confirm the polyolefin resin of the front surface layer and the back surface layer. . Moreover, by analyzing (transmission method) the protective film 9 itself with the infrared spectrophotometer, it is possible to estimate the types of polyolefin resin and inorganic particles of the base material layer. And protective film 9 itself is measured by DSC, and calorie | heat amount of melting and melting | fusing point are calculated | required. Moreover, the thickness of each layer is confirmed by observing the cross section of the protective film 9 with an electron microscope. The above analysis shows the thickness of each layer and the type of resin used. Finally, by burning the protective film 9, the amount of inorganic particles contained in the base material layer 9a can be calculated. If the above method is followed, it can be confirmed what kind of structure the protective film 9 is.

The protective film 9 used in the present invention is not particularly limited. However, in order to reduce the appearance defect of a molded product, for example, there are few so-called fish eyes such as contaminants and foreign matters caused by poor melting of the resin. It is preferable. In particular, considering the influence of appearance defects on the production and molding of industrial protective film 9, the number of fish eyes whose maximum diameter is more than 1 and less than 2 times the thickness of protective film 9 is 10 / it is preferably 100 cm ² or less, more preferably 5/100 cm ² or less. Most preferably, it is 0 / cm ² .

  The other physical properties of the protective film 9 are not particularly limited. However, in consideration of heat bending, the protective film is at a temperature of 130 ° C. which is included in a temperature range in which the heat bending is generally performed. It is preferable that the tensile properties in the flow direction (MD) 9 satisfy the following physical properties. That is, at 130 ° C., the maximum strength until the tensile elongation of MD becomes 50% is preferably 0.5N or more and 2.5N or less. The reason why the tensile elongation is limited to 50% is that it is less likely to be stretched further (50% or more) if it is a normal hot bending process. When the base layer 9a contains inorganic particles, the maximum strength until the tensile elongation of MD reaches 50% is relatively low in the range of 0.5N to 2.5N (for example, Even if the maximum strength is 0.8N or more and 1.3N), the protective film 9 is excellent in heat resistance and can be easily peeled off from a heat-bending product.

  Normally, the higher maximum strength at 130 ° C. is considered to have heat resistance and exhibit excellent effects, but if the maximum strength is too high, necking is likely to occur. Although it is considered, there is a tendency that after the thermal bending process, the end portions of the protective film 9 existing on both surfaces of the optical laminate 1 are fused to each other. On the other hand, if the strength becomes too low, the adhesiveness of the protective film 9 becomes too high after hot bending, and it takes a long time to peel off or tends to be broken.

Therefore, it is preferable that the yield point of the protective film 9 does not appear clearly. In order to obtain such a protective film 9, it is preferable to blend inorganic particles in the base material layer 9a as described above. Specifically, in MD, the difference (F _max −F ₅₀ ) between the maximum strength (F _max ) until the elongation at 130 ° C. reaches 50% and the strength (F ₅₀ ) when the elongation is 50%. ) Is preferably 0.20 N or less, more preferably 0.15 N or less, and even more preferably 0.10 N or less. The smaller the difference, the more clearly the yield point does not appear and the necking phenomenon does not become prominent. Therefore, in the thermal bending process, the fusion of the ends of the protective film 9 existing on both sides can be further suppressed, and the peeling is performed. It is possible to improve the operability when performing. Therefore, in MD, the strength when the elongation at 130 ° C. is 50% may be the maximum strength (F _max ), but in order to do so, other physical properties are reduced, or production of the protective film 9 itself is produced. The lower limit of the difference is preferably 0.01N because the property tends to decrease.

In addition, the protective film 9 has a maximum strength of 0.1 to 1.5 N / mm ² until the tensile property in the direction perpendicular to the flow direction (TD) reaches a tensile elongation of 50% at a temperature of 130 ° C. It is preferable that An excellent effect is exhibited when the tensile properties of the TD of the protective film 9 satisfy the above range. In particular, when a circular heat bending process is performed, since MD and TD are balanced, a particularly excellent effect is exhibited.

Further, the protective film 9 has MD and TD tensile properties at 23 ° C., and the MD elongation is 100 to 600%, the breaking strength is 5 to 15 N / mm ² , the TD elongation is 100 to 600%, and the breaking strength is 5 It is preferably ˜15 N / mm ² .

  The protective film 9 used in the present invention can be formed by a known method. Although the resin used for the base material layer 9a depends on the blending ratio of the inorganic particles, the base material layer 9a can be formed while kneading the first polyolefin resin and the inorganic particles in a film forming machine. . However, in the resin used for the base material layer 9a, when the blending ratio of the inorganic particles contained in the base material layer 9a increases, first, the first polyolefin resin and the inorganic particles are melted by a biaxial stretching machine or the like. A kneaded and pelletized product is preferably used.

  Examples of the method for forming the protective film 9 include the following methods. Specifically, the film can be formed using a multilayer film forming machine such as an extrusion molding machine equipped with a T die or an inflation molding machine equipped with a circular die. Using such a multilayer film forming machine, the first polyolefin resin (including inorganic particles), the second polyolefin resin, and the third polyolefin resin to be used in each layer are equal to or higher than the melting point of each resin. Preferably, melting and film formation may be performed using the multilayer film forming machine at a temperature of 20 ° C. or higher than the melting point and a temperature lower than the temperature at which each resin decomposes. The thickness of each layer can be controlled by adjusting the lip interval of the die. Moreover, the ear | edge part which does not become a product at the time of film forming can be collect | recovered, and it can also be mixed and used for resin which forms the base material layer 9a into a film.

  The protective film 9 obtained by this method may be either a stretched film or an unstretched film, but is preferably an unstretched film in consideration of shrinkage during hot bending.

(Manufacture of optical laminated body 1)
In the optical laminated body 1 of the present invention shown in FIG. 1 or 2 described above, various design changes are possible. For example, in the example of FIGS. 1 and 2, the protective film 9 is provided on both of the pair of transparent sheets 3 and 3, but can be provided only on one transparent sheet 3. Further, a hard coat layer, an antireflection layer, or the like may be formed on the surface of the transparent sheet 3. However, the protective film 9 is preferably provided on both of the transparent sheets 3 and 3 in order to increase the productivity of the heat-bending processed product and suppress the appearance defect. The optical layered body 1 of the present invention exhibits particularly excellent effects when the optical layered body 1 having the protective film 9 on both sides is subjected to heat bending.

  The optical laminated body 1 of this invention shown by FIG.1 and FIG.2 sticks the protective film 9 to the one surface of the transparent sheet which forms the transparent sheet 3 previously by thermocompression bonding etc., and produces a transparent sheet with a protective film. The optical functional layer 5 can be laminated on the other surface of the transparent sheet.

  The optical functional layer 5 is laminated by, for example, preparing a coating liquid in which a binder resin (or a prepolymer thereof) and an optical functional material for forming the optical functional layer 5 are dispersed or dissolved in an organic solvent. The liquid can be applied to the other surface of the transparent sheet and dried by heating.

  In the case where the adhesive layer 7 is interposed between the optical functional layer 5 and the transparent sheet 3, a coating in which an adhesive layer forming resin (for example, a urethane resin or a prepolymer thereof) is dissolved or dispersed in an organic solvent. After preparing a liquid and applying this coating liquid to the other surface of the transparent sheet with a protective film described above, the optical functional layer 5 may be laminated in the same manner as described above.

  The optical layered body 1 of the present invention obtained by the above-described method can be used as it is for secondary processing or the like, but in order to improve the adhesion of the obtained optical layered body 1 and during the secondary processing. In order to prevent foaming or the like, the following treatment is preferably performed prior to the secondary processing. For example, it is preferable to deaerate the optical layered body 1 immediately after production by standing at a temperature of 20 to 70 ° C. for 4 hours or more under normal pressure or reduced pressure. Furthermore, it is preferable to leave this standing laminate at a temperature of 60 to 130 ° C. for 30 minutes to 3 hours. Thereby, foaming at the time of secondary processing can be effectively prevented.

Further, when an isocyanate compound is added to the optical functional layer 5 in addition to the urethane resin (urethane-urea resin), the crosslink density is increased and the adhesion between the optical functional layer 5 and the transparent sheet 3 is increased. Further, it is preferable that the humidification treatment is performed at a temperature of room temperature to 100 ° C and a humidity of 30 to 100% RH. Furthermore, when such a humidification process is performed, the excessive water | moisture content which exists in the optical laminated body 1 can be removed by leaving still at 40-130 degreeC under a normal pressure or a vacuum. Secondary processing of optical laminate 1)
The optical layered body 1 of the present invention that has been subjected to the above-described treatment is usually molded into a desired optical article by secondary processing. For example, the optical laminated body 1 is die-cut into a desired shape (die-cutting process), and then a spherical shape that is applied to lenses, sunglasses, goggles, etc. is formed by thermal bending.

  In the die cutting process, a blade such as a Thomson blade, a pinnacle blade, an engraving blade, or an etching blade is used. From the viewpoint of processing stability and economy, it is preferable to use a Thomson blade. Examples of the shape of the Thomson blade include a double blade, a single blade, a double blade, a triple blade, a double blade, and the blade angle of the blade edge is preferably in the range of 25 to 60 °.

  The thickness of the blade is preferably 0.3 to 2.0 mm, and the material is preferably all steel having a Shore hardness of 30 to 90. As for the Shore hardness, it is also possible to adjust the sharpness by increasing only the hardness of the blade edge.

  When the optical laminate 1 of the present invention is punched with a Thomson blade, a blade having a blade angle of 45 ° or less is used in consideration of the cutting property of the protective film 9 attached to the optical laminate 1. More preferably, the blade is most preferably 30 ° or less. When the blade angle of the Thomson blade to be used exceeds 60 °, the cutting property of the protective film 9 is deteriorated, so that the protective film 9 extends to the end of the optical laminate 1 to generate a filamentous material, or the protective film 9 The end portion of the lens may be lifted, which may cause a defect in the finally obtained plastic lens and a decrease in yield.

  Further, the pressure at the time of die cutting may be determined as appropriate depending on the material of the optical laminate 1 to be die-cut, but the optical laminate 1 of the present invention is subjected to a pressure of 500 to 1000 kg per sheet. It is preferable to remove.

  In the optical laminated body 1 of the present invention, for example, when the protective film 9 having a laminated structure as shown in FIG. 2 is used, the end of the protective film 9 at the time of die cutting is effectively prevented from being lifted. Therefore, generation of thread-like materials such as burrs is effectively suppressed. For example, when this optical layered body 1 is punched into a circle, the generation of a thread-like material having a length of 2 mm or more generated at the outer edge portion (end portion) is effectively suppressed. That is, as shown in the examples described later, the number of the filamentous material when the optical laminated body 1 is punched to a diameter of 80 mm is 20 or less. For the measurement of the filamentous material, a digital microscope (manufactured by Keyence Co., Ltd., VHX-2000) was used to confirm the filamentous material having a length of 2 mm or more present on the outer periphery of the sheet punched into a circular shape having a diameter of 80 mm. It is measured by counting the number of the filaments.

  The hot bending process is performed by a hot press process using a predetermined mold, a pressurizing process, a vacuum suction process, or the like. In particular, when vacuum suction processing is performed, the optical laminate of the present invention can be closely adhered to the mold because the floating of the protective film edge is suppressed, and its molding processability is greatly improved. This is preferable because it is possible.

  In the hot press processing, first, a desired spherical convex mold and a concave mold are mounted on a hot press machine, and the optical laminate 1 is pressed between the molds with a fixing jig, and the convex is formed. The mold and the concave mold are heated. Subsequently, it can be bent into a desired spherical shape by pressing with this heated mold from both sides of the optical laminate 1. In the case of hot pressing, it is also possible to perform bending using only a convex mold without using a concave mold. In the case of performing hot press processing, not only the mold but also the entire atmosphere in which hot pressing including the optical laminate 1 is performed may be performed.

  The pressing process uses an apparatus having a desired spherical concave mold. The optical laminate 1 of the present invention is fixed to the concave mold by a fixing jig, and a mold capable of injecting compressed air is placed on the lower surface side of the optical laminate 1, and the whole is heated by a heater. Next, compressed air is injected from the lower surface side of the optical layered body 1 to be deformed into the shape of a concave mold.

  The vacuum suction processing uses a device having a desired spherical concave mold as in the pressurization processing. The optical laminate 1 of the present invention is installed in this concave mold, or is fixed with a fixing jig, and the whole is heated with a heater. Next, the optical laminate 1 is deformed into the shape of the concave mold by sucking under reduced pressure from the inside of the concave mold. Moreover, the optical laminated body 1 can also be shaped by the heat bending process using pressure processing and vacuum suction processing together.

  Although the temperature at the time of performing the above-described heat bending process may be appropriately determined depending on the material of the transparent sheet 3 used in the optical laminate 1, it is preferably performed at a temperature of 120 to 200 ° C.

  In the optical layered body 1 of the present invention, since the protective film 9 having a small number of large optical impurity particles is selected and used, the dent on the surface of the transparent sheet 3 is not affected by the heat bending process. Generation | occurrence | production is suppressed effectively, the external appearance defect in the case of peeling off the protective film 9 is prevented effectively, and the outstanding optical characteristic is exhibited stably.

  In addition, the above heat bending processes can also be performed before a die cutting process.

  The optical laminate 1 subjected to the secondary processing as described above can be directly sold as an optical article, and can be used as an optical article by peeling off the protective film 9. Moreover, after peeling off this protective film, it can also be integrated with a predetermined optical base material and used as an optical article such as a lens.

The integration with the optical base material is performed by mounting the optical laminate 1 from which the protective film 9 has been peeled off in a predetermined mold, and forming a polymer (for example, polycarbonate) by injection molding using a so-called inner mold. ) In a mold and can be performed simultaneously with the molding of the optical substrate. The surface of the optical substrate thus formed (the surface of the transparent sheet 3 of the optical layered body 1) is appropriately formed with a hard coat layer or a thin film of a metal oxide such as SiO ₂ , TiO ₂ , or ZrO ₂ . Processing such as antireflection treatment or antistatic treatment such as vapor deposition or coating of a thin film of an organic polymer, and secondary treatment can also be performed.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not restrict | limited by these Examples. Hereinafter, the compound used in each layer, the formation method of the layer, and the like will be described.

(Optical function layer 5)
Compound for exerting optical function PC1: Compound represented by the following formula

(Base material for forming the optical functional layer 5)
(Base material: Preparation of adhesive A)
A three-necked flask having a stirring blade, a cooling tube, a thermometer, and a nitrogen gas introduction tube was charged with 251.9 g of polycarbonate diol having a number average molecular weight of 800 and 100 g of isophorone diisocyanate and reacted at 110 ° C. for 7 hours under a nitrogen atmosphere. A prepolymer was synthesized. After completion of the reaction, the reaction solution was cooled to around 30 ° C., dissolved in 1515 g of tetrahydrofuran (THF), and then 23.6 g of bis- (4-aminocyclohexyl) methane, which is a chain extender, was added dropwise. Reacted for hours. Thereafter, 7.7 g of 1,2,2,6,6-pentamethyl-4-aminopiperidine was added dropwise and reacted at 25 ° C. for 1 hour to obtain a THF solution of urethane-urea resin. Here, 11.5 g of the above photochromic compound (PC1), 40 g of an isomer mixture of 4,4′-methylenebis (cyclohexyl isocyanate), and ethylenebis (oxyethylene) bis [3- (5-tert-butyl) as an antioxidant. -4-hydroxy-m-tolyl) propionate] and 4 g of DOW CORNING TORAY L-7001 as a surfactant were added, and the mixture was stirred and mixed at room temperature to obtain an adhesive A. The urethane-urea resin contained in this adhesive A had a softening point of 105 ° C. Using this adhesive A as a base material, the optical functional layer 5 was formed by the method described in Examples.

(Optical functional layer 5; Preparation of polarizing film)
When a polarizing film was used for the optical function layer 5, the polarizing film was adjusted by the following method.

  A 75 μm-thick polyvinyl alcohol film (trade name: VF-PS # 7500; manufactured by Kuraray Co., Ltd.) is heated to 30 ° C. using a mixed solution (staining solution) of 0.04% iodine and 0.4% potassium iodide. The film was dyed in the held dyeing bath while being stretched to be 3 times the length of the original fabric. This film was further immersed in a 3.5% boric acid aqueous solution (stretching bath) and stretched so as to be 6 times as much as the original fabric, thereby producing a polarizing film (thickness 27 μm). The obtained polarizing film had a luminous transmittance of 42.5% and a degree of polarization of 99.2%. This polarizing film was used as a part of the optical function layer 5.

(Base material for forming the adhesive layer 7 (adhesives B and C))
(Base material; preparation of adhesive B)
A three-necked flask having a stirring blade, a cooling tube, a thermometer, and a nitrogen gas introduction tube was charged with 220 g of polycarbonate diol having a number average molecular weight of 1000 and 100 g of isophorone diisocyanate, and reacted at 110 ° C. for 7 hours in a nitrogen atmosphere. Was synthesized. After completion of the reaction, the reaction solution was cooled to around 30 ° C. and dissolved in 1550 g of propylene glycol monomethyl ether, and then 36 g of isophoronediamine as a chain extender was added dropwise and reacted at 25 ° C. for 1 hour. Thereafter, 2 g of n-butylamine was further added dropwise and reacted at 25 ° C. for 1 hour to obtain a propylene glycol monomethyl ether solution of urethane-urea resin. Here, 2.0 g of DOW CORNING TORAY L-7001 was added as a surfactant, and the mixture was stirred and mixed at room temperature to obtain an adhesive B. The urethane-urea resin contained in this adhesive B had a softening point of 150 ° C. Using this adhesive B as a base material, the adhesive layer 7 was formed by the method described in Examples.

(Base material: Preparation of adhesive C)
A three-necked flask having a stirring blade, a cooling tube, a thermometer, and a nitrogen gas introduction tube was charged with 251.9 g of polycarbonate diol having a number average molecular weight of 800 and 100 g of isophorone diisocyanate and reacted at 110 ° C. for 7 hours under a nitrogen atmosphere. A prepolymer was synthesized. After completion of the reaction, the reaction solution is cooled to around 30 ° C. and dissolved in 1515 g of THF, and then 23.6 g of bis- (4-aminocyclohexyl) methane, which is a chain extender, is added dropwise and reacted at 25 ° C. for 1 hour. It was. Thereafter, 7.7 g of 1,2,2,6,6-pentamethyl-4-aminopiperidine was added dropwise and reacted at 25 ° C. for 1 hour to obtain a THF solution of urethane-urea resin. Here, 40 g of an isomer mixture of 4,4′-methylenebis (cyclohexyl isocyanate) and 0.6 g of DOW CORNING TORAY L-7001 as a surfactant were added, followed by stirring and mixing at room temperature to obtain an adhesive C. . The urethane-urea resin contained in the adhesive C had a softening point of 105 ° C. Using this adhesive C as a base material, the adhesive layer 7 was formed by the method described in Examples.

(Characteristic evaluation of the protective film used)
(Melting point, heat of fusion, softening start temperature)
In the present invention, the melting point of the protective film 9 was measured by the following method using a differential scanning calorimeter (DSC8230) manufactured by Rigaku Corporation. About 5 mg of the protective film 9 serving as a sample was weighed in an aluminum sample pan, and alumina was used as a reference. Measurement was performed from 40 ° C. to 300 ° C. at a temperature rising rate of 10 ° C./min in a nitrogen atmosphere. The melting point was obtained by reading the peak top value that can be measured according to JIS-K7121. Hereinafter, this measurement may be referred to as “DSC”.

(Physical properties of protective film)
The protective film 9 used in Examples and Comparative Examples was evaluated for physical properties under the following conditions.

  First, the protective film used as a sample was cut out so that 25 mm wide × 10 cm long and the MD direction was 10 cm long. Using this protective film as a test piece, it was mounted on a testing machine (Autograph AGS-500NX, manufactured by Shimadzu Corporation) with a distance between chucks of 50 mm, and a tensile test was performed at a crosshead speed of 100 mm / min. This tensile test was performed in an atmosphere at 130 ° C.

As measured values, the maximum strength (F _max ) until the elongation reaches 50% and the strength (F ₅₀ ) when the elongation is 50% are read, and the difference (F _max −F ₅₀ ) is read from the measured values. ) Was calculated. In addition, this measured value is the value which measured the protective film 9 itself before affixing on the transparent sheet 3. FIG.

Example 1
(Preparation of optical laminate 1)
An optical laminate 1 having the configuration shown in FIG. 2 was prepared. First, a polycarbonate sheet (thickness 400 μm, transparent sheet 3) having a protective film 9 laminated on one side was prepared.

The protective film used was
The inner layer 9b is a layer mainly composed of a linear low density polyethylene (second polyolefin resin LLDPE, melting point 120 ° C. (measurement result of the protective film 9)) having a film thickness of about 16 μm.
The base material layer 9a is mainly composed of polypropylene (first polyolefin resin PP, melting point 165 ° C. (measurement result of the protective film 9)) having a film thickness of about 48 μm, and titanium oxide (TiO ₂ ) is added to 100 parts by mass of polypropylene. A layer containing 10 parts by mass,
Laminated product of outer layer 9c having a film thickness of about 16 μm (third polyolefin resin PP, melting point 165 ° C. (measurement result of protective film 9)) as a main component (indicated as protective film A in Tables 1 to 3) Film). In addition, the same polypropylene (PP) was used for the first polyolefin resin and the third polyolefin resin.

  The area ratio [(I) / (II)] of the heat of fusion (I) of 80 ° C. to 135 ° C. and the heat of fusion (II) of 145 ° C. to 175 ° C. determined by DSC was 66/34. . DSC measurement was carried out by the above method.

The adhesive layer 7 was formed on the surface opposite to the protective film 9 of the polycarbonate sheet (thickness 400 μm, transparent sheet 3) on which the protective film 9 was laminated on one side. First, by using a coater (manufactured by Tester Sangyo), the adhesive B is coated on the polycarbonate sheet at a coating speed of 0.5 m / min and dried at a drying temperature of 110 ° C. for 3 minutes.
Two polycarbonate sheets having a protective film 9 laminated thereon and an adhesive layer 7 having a thickness of 5 μm on the opposite side were prepared.

  Adhesive A is coated on a 50 μm OPP film (stretched polypropylene film) at a coating speed of 0.3 m / min, dried at a drying temperature of 100 ° C. for 5 minutes, and an optical functional layer is formed on the OPP film. 5 was prepared. The optical functional layer 5 was placed on the adhesive layer 7 of one polycarbonate sheet prepared by the above method, and was laminated using a laminate roll. The thickness of the optical functional layer 5 having photochromic characteristics was 40 μm.

  Subsequently, the OPP film was peeled from the polycarbonate sheet (transparent sheet 3) / adhesive layer 7 / optical functional layer 5 / OPP film having photochromic characteristics prepared in the above-described manner and laminated in this order. The obtained structural body and another sheet of the polycarbonate sheet having the protective film 9 and the adhesive layer 7 prepared by the above method, the optical functional layer 5 of the structural body and the adhesive layer 7 of the polycarbonate sheet are In order to join, it pressed using the lamination roll. Next, the optical layered body thus obtained was allowed to stand at 60 ° C. under vacuum (500 Pa) for 12 hours (degassing step), and then heat-treated at 120 ° C. for 2 hours (heating step). Further, an optical layer having photochromic properties is obtained by performing a humidification process (humidification process) for 20 hours at 70 ° C. and 90% RH, and finally leaving it at 80 ° C. under vacuum (500 Pa) for 5 hours (drying process). Body 1 was obtained.

  A part of the obtained optical laminated body 1 was taken out, and the physical properties before hot bending were confirmed. The peel strength (strength for peeling the polycarbonate sheet and the polycarbonate sheet) was 200 N / 25 mm in the initial stage and 180 N / 25 mm after the boiling test. The photochromic characteristics measured by peeling off the protective film 9 were a maximum absorption wavelength of 585 nm, a color density of 1.0, a fading speed of 45 seconds, and a durability of 93%. The peel strength between the optical laminate and the protective film was 1.0 N / 25 mm in the initial stage, and 1.0 N / 25 mm after heating at 150 ° C. for 30 minutes. (The measurement conditions for these peel strengths are as follows. The measurement conditions for the photochromic properties are the same as those after hot bending).

(Peel strength; optical laminate)
The obtained optical layered product was used as a test piece having an adhesive part of 25 × 100 mm, mounted on a testing machine (Autograph AGS-500NX, manufactured by Shimadzu Corporation), and subjected to a tensile test at a crosshead speed of 100 mm / min. The peel strengths 1) and 2) below were measured.
1) The initial peel strength was tested as described above.
2) The peel strength after the boiling test was measured as described above after the test piece cut out in size was immersed in boiling distilled water for 1 hour.

(Peel strength; between optical laminate and protective film)
The peel strength between the optical laminate and the protective film is attached to a tester (Autograph AGS-500NX, manufactured by Shimadzu Corporation), and the tensile test optical laminate is peeled at a crosshead speed of 100 mm / min by the same method as the peel strength. It was measured. The measurement was performed using a test piece of 25 mm width × 10 cm length.

(Secondary processing of optical laminate 1)
(Die cutting)
In order to mold the obtained optical laminate 1 into a lens, the optical laminate 1 with the protective film is die-cut using a Thomson blade (both blades, blade angle 42 °), and a disk having a diameter of 80 mm. 20 sheets were obtained. The obtained disk-shaped sheet had a good product acquisition yield of 100% for appearance evaluation 1. The method of appearance evaluation 1 is as follows.

(Appearance evaluation 1)
Twenty disk-shaped sheets having a diameter of 80 mm are produced from the obtained optical laminated body 1, and “20 or less thread-like foreign matters having a length of 2 mm or more are formed at the end of the disk-shaped sheet” and “disk-shaped. The number of disc-shaped sheets satisfying both “the float of a protective film 0.5 mm wide or more at the edge of the sheet is less than a quarter of the outer circumference” is obtained, and the percentage of the disc-shaped sheets that are good is obtained. Calculated as a rate. Evaluation was evaluated visually.

(Hot bending)
The obtained disk-shaped sheet was bent into a spherical shape by vacuum suction processing (thermal bending processing). The vacuum suction processing was performed by placing a concave mold having a diameter of 90 mm in an atmosphere at 150 ° C. and performing vacuum suction with a vacuum pump from the hole in the center of the concave mold. The processing time was about 20 minutes per sheet, and the optical laminate 1 processed into a spherical shape was obtained by removing from the mold. Prior to the vacuum suction processing, the optical laminate 1 was preheated at 80 ° C. for 1 hour under vacuum. The obtained optical layered body 1 had an appearance evaluation 2 result of 60%. The method of appearance evaluation 2 is as follows.

(Appearance evaluation 2)
20 disk-shaped sheets having a diameter of 80 mm are produced from the obtained optical laminated body 1 and then subjected to a heat bending process, and the protective films 9 on both sides are not fused at the ends of the disk-shaped sheet. , And after the protective film is peeled off, no residue of the protective film is observed at the end of the disk-shaped sheet. Was calculated as the non-defective product acquisition rate. Evaluation was evaluated visually.

(Injection molding)
The protective film 9 of the obtained optical layered body 1 having a spherical shape was peeled off on both sides, then placed in a mold of an injection molding machine and heated to 100 ° C. The injection molding machine was filled with polycarbonate resin pellets (Panlite manufactured by Teijin Kasei Co., Ltd.) preheated at 120 ° C. for 5 hours, heated and melted at 300 ° C. and 60 rpm, and injected at an injection pressure of 14,000 N / cm ² . Thereafter, a plastic lens (optical article) integrated with polycarbonate resin (injection molding) was manufactured from the mold. The obtained plastic lens had an appearance evaluation 3 result of 80%, and the photochromic properties were a maximum absorption wavelength of 585 nm, a color density of 1.0, a fading speed of 45 seconds, and a durability of 93%. The method of appearance evaluation 3 and the evaluation method of photochromic properties are described below.

2. Evaluation of plastic lens (optical article) (Appearance evaluation 3)
It was confirmed visually and by a digital microscope (manufactured by Keyence Corporation, VHX-2000) whether or not a defective portion was present in the obtained plastic lens (those from which the protective film was peeled off). In the evaluation by the digital microscope, the irregularities having a diameter of 30 μm or more were judged as poor appearance. When even one defective portion exists per lens, it was determined as a defective lens, and the ratio of non-defective lenses to the obtained 20 lenses was calculated as a lens molding yield.

(Photochromic characteristics)
A xenon lamp L-2480 (300W) SHL-100 manufactured by Hamamatsu Photonics Co., Ltd. was passed through an aeromass filter (manufactured by Corning), and the beam intensity on the surface of the laminate was 365 nm. The color was developed by irradiation for 120 seconds at 2.4 mW / cm ² and 245 nm = 24 μW / cm ² , and the photochromic characteristics of the plastic lens were measured.

  1) Maximum absorption wavelength (λmax): This is the maximum absorption wavelength after color development determined by a spectrophotometer (instant multichannel photo director MCPD1000) manufactured by Otsuka Electronics Co., Ltd. The maximum absorption wavelength is related to the color tone at the time of color development.

  2) Color density [ε (120) −ε (0)]: difference between absorbance ε (120) after irradiation for 120 seconds at the maximum absorption wavelength and absorbance ε (0) without irradiation at the maximum absorption wavelength . It can be said that the higher this value, the better the photochromic properties.

  3) Fading speed [t1 / 2 (sec.)]: When light irradiation is stopped after irradiation for 120 seconds, the absorbance at the maximum wavelength of the sample is 1 / ([ε (120) −ε (0)]). Time required to drop to 2. It can be said that the shorter this time is, the better the photochromic property is.

4) Durability (%) = [(A96 / A0) × 100]: In order to evaluate the durability of color development by light irradiation, the following deterioration acceleration test was conducted. That is, the obtained optical laminate was accelerated and deteriorated for 96 hours using a Xenon weather meter X25 manufactured by Suga Test Instruments Co., Ltd. Thereafter, the color density was evaluated before and after the test, the color density (A0) before the test and the color density (A96) after the test were measured, and the value of [(A96) / A0] × 100] was determined as the residual rate. (%) And used as an index of color durability. The higher the remaining rate, the higher the durability of coloring.
Table 3 shows only the photochromic characteristics of the plastic lens.

Examples 2 to 16, Comparative Example 1
Using the protective film 9 shown in Table 1 and Table 2, an optical laminate 1 and further a lens were produced in the same manner as in Example 1. The results are shown in Table 3. As the inorganic particles, examples of using the same titanium oxide as in Example 1, was described as TiO ₂ in Table 1, it described the blending ratio. Also, examples of using calcium carbonate as the inorganic particles, the calcium carbonate in Table 1 described as CaCO _3, described the blending ratio. In each example, the protective film 9 used was one in which the first polyolefin resin and the second polyolefin resin were the same polypropylene (PP).

  The comparative example 1 is an example using the protective film (protective film Q) which does not contain an inorganic particle in a base material layer. In addition, the protective film Q used was the same polyolefin (PP) as the first polyolefin resin and the second polyolefin resin.

Example 17
(Preparation of optical laminate 1)
First, a polycarbonate sheet (thickness 400 μm, transparent sheet 3) having a protective film 9 laminated on one side was prepared.

The protective film used was
The inner layer 9b is a layer mainly composed of a linear low density polyethylene (second polyolefin resin LLDPE, melting point 120 ° C. (measurement result of the protective film 9)) having a film thickness of about 8 μm,
The base material layer 9a contains polypropylene (first polyolefin resin PP, melting point 165 ° C. (measurement result of the protective film 9)) having a film thickness of about 64 μm as a main component, and contains 20 parts by mass of calcium carbonate with respect to 100 parts by mass of polypropylene. Layer to
Laminated product of outer layer 9c whose main component is polypropylene (third polyolefin resin PP, melting point 165 ° C. (measurement result of protective film 9)) having a film thickness of about 8 μm (indicated as protective film K in Tables 1 to 3) Film). In addition, the same polypropylene (PP) was used for the first polyolefin resin and the third polyolefin resin.

  The area ratio [(I) / (II)] of the heat of fusion (I) from 80 ° C. to 135 ° C. and the heat of fusion (II) from 145 ° C. to 175 ° C. determined by DSC was 81/19. . DSC measurement was carried out in the same manner as in Example 1.

  The adhesive layer 7 was formed on the surface opposite to the protective film 9 of the polycarbonate sheet (thickness 400 μm, transparent sheet 3) on which the protective film 9 was laminated on one side. First, using a coater (manufactured by Tester Sangyo), the adhesive B was applied onto the polycarbonate sheet (thickness 400 μm, transparent sheet 3) at a coating speed of 0.5 m / min, and a drying temperature of 110 ° C. By drying for 2 minutes, the protective film 9 was laminated | stacked and the two polycarbonate sheets which have the adhesive layer 7 with a film thickness of 5 micrometers on the other side were prepared.

  The adhesive A was coated on a 50 μm OPP film (stretched polypropylene film) at a coating speed of 0.3 m / min, dried at a drying temperature of 100 ° C. for 5 minutes, and the optical functional layer 5 was coated on the OPP. Prepared. The optical functional layer 5 was placed on the adhesive layer 7 of one polycarbonate sheet prepared by the above method, and was laminated using a laminate roll. The thickness of the optical functional layer 5 having photochromic properties was 40 μm (hereinafter, the obtained structure may be referred to as “structure X”).

  Adhesive C was coated on a 50 μm OPP film (stretched polypropylene film) at a coating speed of 0.3 m / min, dried at a drying temperature of 100 ° C. for 5 minutes, and adhered onto the OPP film. Layer 7 (Adhesive C) was prepared. The adhesive layer 7 was placed on the adhesive layer 7 (adhesive B) of one polycarbonate sheet prepared by the above method, and pasted using a laminate roll. The thickness of the newly provided adhesive layer 7 was 40 μm, and the total thickness of the two types of adhesive layers was 45 μm (hereinafter, the obtained structure may be referred to as “structure Y”).

  Next, the OPP film is peeled from the polycarbonate sheet / adhesive layer 7 (adhesive B) / optical functional layer 5 / OPP film having photochromic properties prepared in the above-mentioned method (structure X) laminated in this order, Furthermore, the OPP film was also peeled off from the polycarbonate sheet / adhesive layer 7 (adhesive B) / adhesive layer 7 (adhesive C) / OPP film laminated in this order (structure Y). The obtained polarizing film (optical functional layer 5) was pressed with a laminating roll so that the polarizing film (optical functional layer 5) was bonded between the optical functional layer 5 and the adhesive layer 7 (adhesive C) of the two types of structures obtained. Next, the optical layered body thus obtained was allowed to stand at 60 ° C. under vacuum (500 Pa) for 12 hours (degassing step), and then heat-treated at 120 ° C. for 2 hours (heating step). Further, a humidification treatment (humidification process) is performed at 70 ° C. and 90% RH for 20 hours, and finally, the mixture is left at 80 ° C. under vacuum (500 Pa) for 5 hours (drying process). The optical laminated body 1 which has this was obtained.

  The obtained optical laminate 1 has an initial peel strength of 150 N / 25 mm and 120 N / 25 mm after the boiling test, and the peel strength between the optical laminate and the protective film is 1.0 N / 25 mm before the initial heating, After heating at 150 ° C. for 30 minutes, it was 1.0 N / 25 mm. The photochromic characteristics measured by peeling off the protective film 9 were a maximum absorption wavelength of 585 nm, a color density of 1.0, a fading speed of 45 seconds, and a durability of 93% (these measurement conditions are the same as in Example 1). .)

  Furthermore, the luminous transmittance of the (optical) laminate obtained by peeling off the protective film 9 was 41.0%, and the degree of polarization was 99.1%. The luminous transmittance and the degree of polarization were performed as follows.

[Visibility transmittance (before color development)]
Using the obtained laminate as a sample, the luminous transmittance of the laminate before ultraviolet irradiation was measured using an ultraviolet-visible spectrophotometer UV-2550 manufactured by Shimadzu Corporation.

[Degree of polarization (before color development)]
Using the obtained laminate as a sample, a single transmittance (Ts), parallel transmittance (Tp) and orthogonal transmittance (Tc) were measured using an ultraviolet-visible spectrophotometer UV-2550 manufactured by Shimadzu Corporation. (P) was determined by the following equation.

Polarization degree (P) (%) = {(Tp−Tc) / (Tp + Tc)} 1/2 × 100
Note that Ts, Tp, and Tc are Y values measured with a two-degree field of view (C light source) of JIS Z 8701 and corrected for visibility.

(Secondary processing of optical laminate 1)
The optical laminate 1 was subjected to secondary processing in the same manner as in Example 1 except that the optical laminate 1 having the polarization characteristics and the photochromic properties was used. The evaluation results are shown in Table 3.

  As is apparent from Examples 1 to 17, when the protective film 9 of the present invention was used, the final appearance of the lens was good, and the molding yield was excellent.

DESCRIPTION OF SYMBOLS 1 Optical laminated body 3 Transparent sheet 5 Optical functional layer 7 Adhesive layer 9 Protective film 9a Base material layer 9b containing 1st polyolefin resin and inorganic particle, and melting | fusing point is the range of 150 degreeC or more and 175 degrees C or less 2nd polyolefin type Inner layer 9c containing a resin and having a melting point in the range of 100 ° C. or more and 125 ° C. or less. Outer layer containing the third polyolefin resin and having a melting point in the range of 150 ° C. or more and 175 ° C. or less

Claims (8)

In the optical laminate in which the optical functional layer has a basic structure sandwiched between a pair of transparent sheets, and a protective film is directly laminated on the surface of at least one transparent sheet.
The protective film is
A base material layer containing 5 to 50 parts by mass of inorganic particles with respect to 100 parts by mass of the first polyolefin-based resin and having a melting point in the range of 150 ° C. or higher and 175 ° C. or lower;
Including a second polyolefin-based resin, and having at least two layers with an inner layer having a melting point in the range of 100 ° C. or more and 125 ° C. or less,
The optical laminated body, wherein the inner layer is in close contact with the surface of the transparent sheet. The protective film is
The base material layer opposite to the inner layer further comprises an outer layer containing a third polyolefin resin and having a melting point in the range of 150 ° C or higher and 175 ° C or lower. The optical laminated body as described.   When the thickness of the protective film is 30 μm or more and 200 μm or less, and the thickness of the inner layer is 1, the thickness ratio of the base material layer is 2 to 10, and the thickness ratio of the outer layer is 0.5 to The optical laminate according to claim 2, wherein the optical laminate is 2.   The optical laminate according to any one of claims 1 to 3, wherein the protective film is directly laminated on the surfaces of both transparent sheets.   The optical laminate according to claim 1, wherein the inorganic particles are calcium carbonate. The transparent sheet is a polycarbonate sheet;
The optical layered product according to any one of claims 1 to 5, wherein the optical functional layer comprises a photochromic compound and a urethane resin.   A die-cut product comprising the optical laminate according to claim 1.   A hot-bending product comprising the optical laminate according to claim 1.

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